Cane Tops and Trash.
First in the series of by-products in the manufacture of sugar, comes cane tops. The amount of this material produced per hectare will depend upon various factors, including the variety of cane, its stage of maturity, etc. The less of these tops, of course, that may be produced for a given amount of cane, the better it will be for the growers, nevertheless they have a good feeding value if properly handled.
Professor Dodson,[1] director of the Louisiana Experiment Station, states that he found cane tops to have the following composition:
| Per cent. | |
| Protein | 1.53 |
| Fat | 0.41 |
| Carbohydrate | 15.62 |
| Fiber | 8.87 |
| Water | 71.50 |
| Ash | 2.07 |
The fiber content would be slightly higher and the water content lower, for tropical cane, since maturity is completely reached before harvest begins. It may be seen from the above analyses that this makes a most excellent feed for work animals. Certainly greater advantage should be taken of this feeding stuff than is usually done, since there is a scarcity of pasturage near the end of the harvest season and the animals become needlessly thin on account of lack of feed. At present very little of this material is utilized, but instead is burned on the field with the rest of the trash. If the tops are removed and used as a stock feed, only the leaves and pieces of stalk remain, and these make a good fertilizer for cane lands.
It is the general custom in these Islands to burn all of this material as soon as the crop is harvested. The object of this burning is to destroy any insects that may be present, as well as to facilitate subsequent cultivation. In the writer’s opinion neither of these reasons is sufficiently well based, since in this country large numbers of troublesome cane insects are not found. If they were present in sufficient quantities, the trouble could be handled by placing the trash between the rows and properly treating it before plowing it under. This should be the method of disposing of the trash at all times. In this manner the waste material could be utilized, and the organic matter would be even more valuable than that contained in many of the commercial fertilizers. The nitrogen contained, which amounts to from 0.5 to 2 per cent, would be practically all saved, while with the burning method this is completely lost.
In Louisiana, cotton-seed meal forms one of the principal nitrogenous fertilizers for cane lands. This material costs from ₱50 to ₱75 per ton and Dr. Stubbs,[2] in his research, found that the trash burned from each ton of cane caused a loss of nitrogen equal to that contained in 27 pounds of cotton-seed meal. Besides this loss of nitrogen encountered in the burning of the trash, the organic matter which would later form humus is completely destroyed. Soils would retain moisture better during the dry season and be more easily handled if the conservation of organic matter were given greater attention. There is also a great injury done to the remaining stumps and top roots by this burning which is very detrimental when the field is to be used for a ratoon crop. Where cane is badly infested with destructive insects, it is quite another thing. This again brings up the fact that the cane points should be treated with chemicals before planting, in order to complete the work of destroying these insects.